JPH0324499B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel thermosetting resin composition formed by mixing a copolymer containing isopropenylphenol as one component and a phenol resin. More specifically, the present invention relates to a thermosetting resin composition that has excellent curability and provides a cured product with excellent heat resistance, flexibility, and dimensional stability. Conventionally, phenolic resins have relatively good curability and moldability, and their cured products are widely used as molding materials, laminated materials, bonding materials, etc. as materials with well-balanced heat resistance, electrical properties, and mechanical properties. It's being used. However, the biggest drawback of phenolic resin is that it lacks flexibility, making it easy to break when trying to make large molded products, and cracks tend to occur between the metal and the molded product when molded products are inserted with metal. There was a problem. Furthermore, in the field of laminates, many problems have arisen, such as the inability to punch them at low temperatures due to their poor flexibility. moreover,
Because phenolic resin lacks dimensional stability, it has been subject to many limitations in its application to so-called structural members such as electrical equipment, mechanical parts, and automobile parts that require high reliability. Under these circumstances, the present inventors first
It has been discovered that a thermosetting resin composition consisting of a copolymer containing para-isopropenylphenol as one component and a formaldehyde-generating compound provides a cured product with excellent flexibility and heat-resistant dimensional stability (Japanese Patent Application Laid-Open No. 56−59859). However, since copolymers containing para-isopropenylphenol as one component are copolymerized with other polymerizable monomers, their OH value is lower than that of phenolic resins, and therefore, they have a lower OH value than phenolic resins, and therefore have a lower OH value than formaldehyde-generating compounds. There was a problem with hardenability. In order to solve the above-mentioned drawbacks, the inventors of the present invention have made extensive studies and found that a copolymer containing isopropenylphenol as one component (hereinafter abbreviated as P copolymer) and a phenolic resin are mixed. He discovered that the thermosetting resin composition has excellent curability, and that the cured product has excellent heat resistance, greatly improving flexibility and dimensional stability, which were the biggest drawbacks of phenolic resins. This led to an invention. The P copolymer used in the composition of the present invention is
It is a copolymer of isopropenylphenol and one or more other polymerizable monomers. Other polymerizable monomers for producing this P copolymer include the following. For example, styrene, chlorstyrene, bromstyrene, α-methylstyrene, vinyltoluene,
Styrenes such as vinyl xylene, acrylic esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, etc. methacrylic acid esters, acrylonitrile, methacrylonitrile, fumaronitrile, acrylic acid, methacrylic acid, maleic anhydride, acrylamide,
There are copolymerizable monomers such as methacrylamide, isoprene, butadiene, and dicyclopentadiene. Further, the isopropenylphenol used in this P copolymer may be any of the ortho form, meta form, para form, or a mixture thereof. The content of isopropenylphenol in the P copolymer used in the composition of the present invention is 5% in the P copolymer.
-90% by weight, preferably 10-80% by weight.
If the content of isopropenylphenol is less than 5% by weight, the curability of the composition is poor and it is difficult to obtain a cured product with excellent heat resistance. Moreover, if it exceeds 90% by weight, the flexibility and dimensional stability of the cured product will deteriorate. When producing P copolymer, radical polymerization,
Polymerization can be carried out by either ionic polymerization or charge transfer polymerization, but radical polymerization using a radical polymerization initiator is preferable from the viewpoint of ease of reaction control. As the radical polymerization initiator, azobisisobutyronitrile, azobis-
Azo initiators such as 2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, azobis-2-amidinopropane/HCl salt, benzoyl peroxide, lauroyl peroxide, acetylcumene hydroperoxide peroxide, t-butyl hydroperoxide , peroxide-based initiators such as di-t-butyl hydroperoxide, benzoyl peroxide
Examples include redox initiators such as N,N-dimethylaniline and peroxodisulfate-sodium bisulfite. The amount of the initiator used is preferably 0.01 to 10% by weight based on the total amount of various monomers that are raw materials for the P copolymer. The P copolymer can be easily produced by using known polymerization methods such as solution polymerization, suspension polymerization, emulsion polymerization, and bulk polymerization. The P copolymer used has a weight average molecular weight of 500 to 50,000, preferably 1,000 to 30,000. 500
If it is less than 50,000 or more than 50,000, it will not be possible to obtain a thermosetting resin composition that provides a cured product with excellent heat resistance, flexibility, and dimensional stability, which is the object of the present invention. The phenolic resin used in the composition of the present invention can also be a novolak type resin. Novolac-type resins are generally obtained by reacting phenols such as phenol, cresol, xylenol, and resorcinol with formaldehydes such as formaldehyde aqueous solution, paraformaldehyde, and trioxane in a state in which the number of moles of the phenol is in excess using an acid as a catalyst. It will be done. Resol type resins are generally obtained by reacting the phenols and formaldehydes with an alkali as a catalyst in a state where the number of moles of formaldehyde is in excess. The thermosetting resin composition of the present invention is formed by mixing a P copolymer and a phenol resin, but the composition ratios can be varied as necessary. The weight ratio of the combined material and the phenolic resin is 0.05 to 20, preferably 0.1 to 10. The weight ratio of P copolymer and phenolic resin is 0.05
When it is less than 20 or more than 20, it becomes impossible to obtain a thermosetting resin composition that has excellent curability and provides a cured product with excellent heat resistance, flexibility, and dimensional stability. Next, the thermosetting resin composition of the present invention can be cured using a curing agent such as paraformaldehyde or hexamethylenetetramine, if necessary. Further, in the thermosetting resin composition of the present invention,
When mixing P copolymer and phenolic resin,
Mix in granular form by crushing or 80~170℃
Heat for several minutes at a temperature of It may be dissolved and mixed in one or more solvents such as ketones such as methyl isobutyl ketone and cyclohexanone, ethers such as dioxane, tetrahydrofuran, methyl cellosolve, and ethyl cellosolve, and esters such as ethyl acetate and butyl acetate. The thermosetting resin composition of the present invention has good curability, and its curability has well-balanced performance such as excellent heat resistance, flexibility, and dimensional stability. It is extremely useful for a wide range of applications, including molding materials for machine parts and automobile parts, laminated materials such as copper-clad laminates, bonding materials for brakes, resinoid grindstones, and shell molds, paints, and adhesive materials. Next, various application examples of the composition according to the present invention will be described. For use as a molding material, fillers such as wood flour, talc, silica, clay, calcium carbonate, glass fiber, lubricants, colorants, etc. are added to the composition of the present invention, and the mixture is heated at 80°C using a roll, kneader, etc. ~
After kneading at a temperature of 170°C, it can be cooled and pulverized to form a molding material. The molding material thus obtained can be molded using a compression molding machine, a transfer molding machine, an injection molding machine, etc. at a temperature of 120°C to 250°C and a pressure of 30 to 500 kg/cm ² . The molded product obtained has excellent heat resistance, particularly high rigidity when heated, and has excellent flexibility and dimensional stability due to long-term thermal history. In addition, for use as a laminated material, the composition of the present invention is dissolved in the above-mentioned common solvent to form a varnish, and this is impregnated into a base material for a laminated board such as cotton linter paper, and after drying, the composition is laminated, heated, and Press molding to obtain a laminate.
The resulting laminate has high heat resistance, especially high strength when heated, and has good flexibility, allowing punching at low temperatures, and exhibits high reliability with no warping or twisting. ing. Further, for use as a bonding material such as a resinoid grindstone, the composition of the present invention is mixed with abrasive grains, and heated and molded using a compression molding machine to obtain a grindstone. The resulting grindstone has high strength when heated and has excellent flexibility. Further, when used in a paint, the composition of the present invention is dissolved in the above-mentioned solvent to form a varnish, and applied to an adherend,
By curing by heating and drying, a coating film with excellent heat resistance and flexibility can be obtained. below,
The effects of the present invention will be specifically explained using production examples, working examples, and test examples. Production example 1 Paraisopropenylphenol (hereinafter abbreviated as PIPE) is placed in a flask equipped with a stirrer and a condenser.
10 parts of n-butyl acrylate, 90 parts of methyl ethyl ketone (hereinafter abbreviated as MEK), and 4.8 parts of azobisisobutyronitrile (hereinafter abbreviated as AIBN) were charged all at once, and the mixture was heated under stirring and refluxed for 4 hours. Polymerized. Add 2.4 parts of AIBN to 4
The mixture was heated under reflux for a period of time to obtain a copolymer solution with a solid content concentration of 28.0. This solution was dried under reduced pressure at 170°C for 2 hours to obtain 91 parts of P copolymer (1). Gel permeation chromatograph (below)
The weight average molecular weight of this copolymer according to GPC (abbreviated as GPC) is 11000, and the OH
The value was 44 mgKOH/g. Production example 2 In a flask with a stirrer and a condenser,
30 parts of PIPE, 70 parts of methyl methacrylate, 100 parts of MEK
1 part and 4.8 parts of AIBN were added at once, heated under stirring, and refluxed to polymerize for 4 hours. AIBN2.4
The mixture was heated and refluxed for 4 hours to obtain a copolymer solution with a solid content of 43.0%. Add this solution to 170
It was dried under reduced pressure at ℃ for 2 hours to obtain 84 parts of copolymer (2).
The weight average molecular weight of this copolymer by GPC is
6200, and the OH value by the acetylation method is 137 mg.
It was KOH/g. Production example 3 In a flask equipped with a stirrer and condenser,
50 parts PIPE, 50 parts styrene, 70 parts MEK, and
Add 4.8 parts of AIBN all at once and heat while stirring.
The mixture was refluxed and polymerized for 4 hours. Furthermore, 2.4 parts of AIBN was added, and heating and refluxing were continued for 4 hours to obtain a copolymer solution with a solid content concentration of 49.5%. Add this solution to 170
It was dried under reduced pressure at ℃ for 2 hours to obtain 84.5 parts of copolymer (3).
The weight average molecular weight of this copolymer by GPC is:
5300, and the OH value by the acetylation method is 195 mg.
It was KOH/g. Production example 4 In a flask with a stirrer and condenser,
PIPE 60 parts, ethyl acrylate hereafter abbreviated as EA 40
1, 233 parts of MEK, and 4.8 parts of AIBN were charged all at once, and the mixture was heated under stirring to reflux and polymerized for 4 hours. Further add 2.4 parts of AIBN and heat for 4 hours.
The mixture was refluxed to obtain a copolymer solution with a solid content concentration of 28.4%. This solution was dried under reduced pressure at 170°C for 2 hours to obtain 92 parts of copolymer (4). The weight average molecular weight of this copolymer by GPC was 8,600, and the OH value by acetylation method was 237 mgKOH/g. Production example 5 In a flask with a stirrer and condenser
65 parts of PIPE, 25 parts of EA, acrylonitrile (hereinafter
10 parts (abbreviated as AN) and 4.8 parts of AIBN were charged all at once, and the mixture was heated under stirring to reflux and polymerized for 4 hours. Furthermore, 2.4 parts of AIBN was added and heated for 4 hours.
The mixture was refluxed to obtain a copolymer solution with a solid content of 29.0%. This solution was dried under reduced pressure at 170°C for 2 hours to obtain 93 parts of copolymer (5). The weight average molecular weight of this copolymer by GPC was 8900, and the OH value by acetylation method was 270 mgKOH/g. Production example 6 In a flask with a stirrer and a condenser,
75 parts of PIPE, 25 parts of AN, 233 parts of MEK, and
Add 4.8 parts of AIBN all at once and heat while stirring.
The mixture was refluxed and polymerized for 4 hours. Furthermore AIBN2.4
of solids and heated under reflux for 4 hours to reduce the solid concentration.
A 28.0% copolymer solution was obtained. This solution was heated to 170℃.
The mixture was dried under reduced pressure for 2 hours to obtain 92 parts of copolymer (6).
The weight average molecular weight of this copolymer by GPC is
9500, and the OH value by the acetylation method is 185 mg.
It was KOH/g. Production example 7 70 parts of PIPE in an autoclave equipped with a stirrer,
30 parts of butadiene, 233 parts of MEK, and 4.8 parts of AIBN were charged, heated to 80°C with stirring, and polymerized for 8 hours to obtain a copolymer solution with a solid content concentration of 14.8%. This solution was dried at 170°C for 2 hours to obtain 48 parts of copolymer (7). The weight average molecular weight of this copolymer by GPC is 3200, and the OH value by acetylation method is
It was 290mgKOH/g. Production Example 8 70 parts of p-isopropenylphenol oligomer and 30 parts of butadiene in an autoclave equipped with a stirrer.
233 parts of MEK and 4.8 parts of AIBN were charged, heated to 80° C. with stirring, and polymerized for 8 hours to obtain a copolymer solution with a solid content concentration of 11.0%. Add this solution to 170
It was dried at ℃ for 2 hours to obtain 32 parts of copolymer (8).
The weight average molecular weight of this copolymer by GPC is
2000, and the OH value by the acetylation method is 320 mg.
It was KOH/g. Production Example 9 In a flask with a stirrer and condenser, P-
60 parts of isopropenylphenol oligomer,
40 parts of EA, 233 parts of MEK, and 4.8 parts of AIBN were charged all at once, and the mixture was heated under stirring to reflux and polymerized for 4 hours. Further, 2.4 parts of AIBN was added, and the mixture was heated and refluxed for 4 hours to obtain a copolymer solution with a solid content concentration of 18.0%. This solution was dried under reduced pressure at 170°C for 2 hours.
58 parts of copolymer (9) was obtained. The weight average molecular weight of this copolymer by GPC was 2800, and the OH value by acetylation method was 210 mgKOH/g. Example 1 10 parts of the copolymer (1) obtained in Production Example 1, Novolac resin (Novolac #2000 manufactured by Mitsui Toatsu Chemical Co., Ltd., softening point
A thermosetting resin composition A was obtained by pulverizing and mixing 90 parts of Novolak #2000 (92 to 98°C) and 12 parts of hexamethylenetetramine as a curing agent using a pulverizer. Example 2 10 parts of the copolymer (1) obtained in Production Example 1 and 225 parts of resol resin (PL-265 manufactured by Mitsui Toatsu Chemical Co., Ltd., abbreviated as resol PL-265 with a concentration of 40% or less) were mixed with methanol.
50 parts of acetone, and dried under reduced pressure at room temperature for 24 hours to obtain thermosetting resin composition B.
I got it. Example 3 40 parts of the copolymer (2) obtained in Production Example 2, 60 parts of Novolac #2000, and 12 parts of hexamethylenetetramine as a curing agent were ground and mixed in a grinder to form thermosetting resin composition C. Obtained. Example 4 30 parts of copolymer (3) obtained in Production Example 3 and resol
175 parts of PL-265 was dissolved in a solvent consisting of 50 parts of methanol and 50 parts of acetone, and then dried under reduced pressure at room temperature for 24 hours to obtain thermosetting resin composition D. Example 5 70 parts of the copolymer (4) obtained in Production Example 4, 30 parts of Novolac #2000, and 12 parts of hexamethylenetetramine as a hardening agent were ground and mixed in a grinder to form thermosetting resin composition E. Obtained. Example 6 60 parts of copolymer (5) obtained in Production Example 5 and resol
100 parts of PL-265 was dissolved in a solvent consisting of 50 parts of methanol and 50 parts of acetone, and then dried under reduced pressure at room temperature for 24 hours to obtain thermosetting resin composition F. Example 7 40 parts of the copolymer (6) obtained in Production Example 6, 60 parts of Novolak #2000, and 12 parts of hexamethylenetetramine as a curing agent were ground and mixed in a grinder to form a thermosetting resin composition G. I got it. Example 8 40 parts of the copolymer (7) obtained in Production Example 7, 60 parts of Novolak #2000, and 12 parts of hexamethylenetetramine as a curing agent were ground and mixed in a grinder to form a thermosetting resin composition H. I got it. Comparative Example 1 100 parts of Novolac #2000 and 12 parts of hexamethylenetetramine as a curing agent were ground and mixed in a grinder to obtain a thermosetting resin composition H. Comparative Example 2 Resol PL-265 was dried under reduced pressure at room temperature for 24 hours to obtain a thermosetting dry product. Comparative Example 3 Thermosetting resin composition J was obtained by grinding and mixing 100 parts of the copolymer (4) obtained in Production Example 4 and 12 parts of hexamethylenetetramine as a curing agent using a grinder. Comparative Example 4 40 parts of the copolymer (8) obtained in Production Example 8, 60 parts of Novolak #2000, and 12 parts of hexamethylenetetramine as a curing agent were ground and mixed in a grinder to form a thermosetting resin composition I. I got it. Comparative Example 5 70 parts of the copolymer (9) obtained in Production Example 9, 30 parts of Novolac #2000, and 12 parts of hexamethylenetetramine as a curing agent were ground and mixed in a grinder to form a thermosetting resin composition J. I got it. The following tests were conducted on each of the thermosetting resin compositions obtained in Examples 1 to 8 and Comparative Examples 1 to 5. Test method (A) Gelation time According to JIS K6910, each composition is placed on a hot plate at 150℃, time until stringiness disappears (B) Barcol hardness, Charpy impact value, dimensional change of molded product when heated To 100 parts of each composition, add 80 parts of wood flour, 30 parts of calcium carbonate, and 1 part of stearic acid.
After kneading for 3 minutes with a hot roll at 120℃, pulverize,
It was made into molding powder. This molded powder was compressed using a compression molding machine at a temperature of 170° C. and a pressure of 100 kg/cm ² for 5 minutes to obtain a molded body, which was used for each test. Barcoll hardness when heated: 10
Leave it for a minute, take it out, and measure the Barcol hardness after 10 seconds using a Barcoll hardness meter. Shyalpy impact value Based on JISK 6911. Heating dimensional change rate After heating the molded product in a hot air circulation dryer at 170℃ for a specified time, take it out, cool it to room temperature, and measure the dimensional change (shrinkage) rate. (C) Heat bending strength, punching workability, warpage,
Twisting, preparation of laminates: 70 parts of methanol for 100 parts of each composition;
It was dissolved in a mixed solvent consisting of 40 parts of MEK to make a varnish. This varnish is impregnated onto cotton linter paper as a base material for impregnation, and after drying, the resin content is 50%.
A laminated material was obtained. Next, a predetermined number of these laminates were stacked and heated at 150° C. and 80 kg/cm ² for 30 minutes to obtain a laminate with a thickness of 1.5 mm. Bending strength under heat Measure bending strength at 150℃ according to JIS C-6481. Punching workability According to ASTM D-167-44, punching workability was determined at room temperature and 50℃. According to JIS C 6481, the state of warpage and twist of the laminates of each composition obtained was visually determined. 〇…There is no warping or twisting at all. ×…There is warpage and twisting. Test Example 1 Examples 1, 3, 5, 7, 8 and Comparative Example 1,
Using each of the compositions No. 3, 4, and 5, the gelation time was measured by test method (A) in order to examine the curability. Also,
A molded body was prepared using test method (B)-, and the test method was used to examine the heat resistance, flexibility, and dimensional stability of the molded body.
(B) The Barcoll hardness during heating, the Charpy impact value, and the heating dimensional change rate were measured. The results are shown in Table-1.

[Table] Test Example 2 Using each of the compositions of Examples 2, 4, and 6 and Comparative Example 2, a laminate was produced according to Test Method (C)-.
In order to examine the heat resistance, flexibility, and dimensional stability of this laminate, we tested the bending strength under heat using test method (C).
Punching workability, warpage, and twist were measured. The results are shown in Table-2.

【table】

Claims (1)

[Claims] 1. A thermosetting resin composition comprising a phenolic resin mixed with a copolymer containing isopropenylphenol as one component.